1. Field of the Invention
The present invention relates to surveillance systems, and, more particularly, to the reduction of false alarms and false trouble conditions in surveillance systems.
2. Description of the Related Art
Surveillance systems, also known as security systems, are known to include security devices such as motion detectors, door sensors, window sensors, smoke detectors, relays, power supplies, etc., for monitoring a secured area of space. The security device may be either wireless or conventionally hard-wired.
Surveillance systems include a great variety of different installations and security devices. Using identically designed security devices in different installations can provide challenges. For example, security devices can have multiple alarm and trouble condition inputs which may be referred to herein as “sub-inputs.” Not all of the sub-inputs are needed in every installation. Some of the sub-inputs remain unused and vulnerable to false alarms and false trouble conditions. False alarms are one of the biggest problems in the security industry.
A known method of preventing unused sub-inputs from creating false alarms or false trouble conditions includes installing special hardware, such as pull up resistors. Another known method is to begin to monitor the sub-input only when it becomes normal (e.g., not faulted). It is only after the sub-input becomes normal that the monitoring process begins. One problem with this particular solution is that the sub-input can accidentally normalize via noise or invalid communication. If the sub-input normalizes before the user is ready, then an alarm will be generated if the sub-input faults.
What is needed in the art is a security system in which unused sub-inputs are not liable to create false alarms or false trouble conditions.